Historical precursors and analogs are often invoked in an attempt to forecast or justify commercial space endeavors. This is especially true when space advocates attempt to make the case of getting government out of space and letting private enterprise take over.

However, history reveals that government participation in a technologically-based activity has benefits as well as disadvantages. Therefore, it may be well to proceed with caution when invoking historical examples as justifications. This calls for occasional sanity checks, particularly with regard to the current attempt to commercialize space activities. A cursory look at some of the historic precursors may be of value to those involved in commercializing space activities. Keep in mind that the record shows that once a system is put into practice it rarely changed and then only with great difficulty, travail, and often negative consequences.